Single arm wheelchair lift

ABSTRACT

A wheelchair lift configured to be foldable into quadrants by a two-step folding process, wherein the first step folds the platform assembly crosswise and the second step folds the platform assembly in the lengthwise direction. To facilitate the folding, the platform assembly includes first and second inner platforms, and first and second outer platforms. In the first step of the folding process, the first and second inner platforms fold with respect to the first and second outer platforms. In the second step of the folding process, the second inner and outer platforms fold with respect to the first inner and outer platforms.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority from U.S. Provisional Patent Application No. 60/386,339 filed on Jun. 6, 2002, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

[0002] The present invention relates generally to wheelchair platform lift assemblies, and more particularly, to a wheelchair lift that folds into a compact state.

BACKGROUND OF THE INVENTION

[0003] There has been an increasing interest in developing automated devices to facilitate the mobility of wheelchair users. Various platform devices, such as lifts and ramps, have been proposed to assist wheelchair users in getting in and out of vehicles. To ensure the safety of the wheelchair user, the platform device must be large enough and sufficiently durable to support the wheelchair and a person thereon during the loading and unloading process. As a result, a typical platform device can be four to five feet long.

[0004] A problem with lengthy and bulky platforms is that it can be difficult to fit the platform within a standard-size vehicle. When bulky platforms are installed in vehicles, the entry way may have to be widened and components of the vehicle may have to be rearranged to accommodate the sizable platform. To avoid the inconvenience of installing a sizable platform, there is a need for new passenger platforms that have a compact configuration when installed in a vehicle.

[0005] Another problem with bulky wheelchair platforms is that when the platform is installed on one side of the vehicle, the suspension of the vehicle rolls to the side at which the wheelchair platform is installed. Consequently, the platform rolls outboard, i.e., tilts away from the vehicle in a downward slope. The rolling of the vehicle suspension creates an uncomfortable situation for the rider because the platform is no longer horizontal, giving the rider the impression of being in a less safe position while suspended over the ground.

[0006] One known method of resolving the tilting problem is allowing the user to tilt the platform toward the vehicle to correct for the tilting of the platform away from the vehicle caused by the rolling of the suspension. The tilt correction mechanism is a secondary operation that requires a separate actuator and a separate control. To operate the tilt correction mechanism, the platform must first be lifted off of the ground. The user then uses a separate control switch to tilt the platform to compensate for the roll of the vehicle. Once the user has reached a comfortable tilt position, the main control switch is activated to proceed with the motion of the platform into or out of the vehicle. The disadvantage of this system is that a separate actuator and control switch is required for the tilt correction mechanism, complicating the mechanical structure and operation of the platform device.

[0007] Another known solution to the tilting problem is to adjust the platform so that it is permanently tilted towards the vehicle, thus accommodating for the tilt away from the vehicle caused by the rolling of the suspension. The disadvantage of permanently tilting the platform towards the vehicle is that, if the platform is adjusted with too much tilt, the front of the platform does not rest on the ground but remains tilted upwards, above the ground. This problem is especially common on roads with a heavy crown, such as a road with deep gutters.

[0008] Accordingly, there is a need to provide a platform device that levels to a comfortable tilt toward the vehicle without requiring a secondary tilt correction mechanism with a separate control switch.

SUMMARY OF THE INVENTION

[0009] A wheelchair lift configured to be foldable into quadrants by a two-step folding process, wherein the first step folds the platform assembly crosswise and the second step folds the platform assembly lengthwise. To facilitate the folding, the platform assembly includes first and second inner platforms, and first and second outer platforms. In the first step of the folding process, the first and second inner platforms fold with respect to the first and second outer platforms. In the second step of the folding process, the second inner and outer platforms fold with respect to the first inner and outer platforms. The wheelchair lift preferably includes a storage configuration wherein the two-step folding process has been completed.

[0010] The platforms are pivotally connected by hinges. In a preferred embodiment of the invention, the first and second inner platforms are connected to the first and second outer platforms by a first hinge, which pivots about a first axis. The first inner platform is connected to the second inner platform by a second hinge that pivots about a second axis. The first outer platform is connected to the second outer platform by a third hinge that pivots about a third axis. To complete the second fold of the two-step folding process, the second axis must be aligned with the third axis. Accordingly, the third hinge is configured to have a pivot axis that is spaced apart from the third hinge, and co-linear with the pivot axis of the second hinge.

[0011] To facilitate the folding, the wheelchair lift includes a first fold actuating assembly, to fold the platform assembly crosswise, and a second fold actuating assembly, to fold the platform assembly lengthwise. The first fold actuating assembly includes a linking arm pivotally connected to the platform assembly at a second connection point and a platform actuator bar connected to the platform assembly at a second connection point, spaced apart from the first connection point. The first fold actuating assembly folds the platform crosswise by exerting force on the platform assembly at a second connection point in a manner that causes the platform assembly to rotate about the first connection point. The exertion of pressure is preferably accomplished by the engagement of a cam with a cam follower on the platform actuator bar. The second fold actuating mechanism is preferably an electrical actuator, and more preferably, an actuator as described in U.S. Provisional Patent Application No. 60/386,338 filed Jun. 6, 2002 and Ser. No. ______ for Clutch-Driven Limited Force Actuator filed concurrently herewith, the contents of which are incorporated herein by reference. However, it is within the scope of the present invention to utilize a piston and cylinder assembly or other known actuators to cause the second side of the platform assembly to pivot with respect to the first side.

[0012] The wheelchair lift of the present invention preferably includes a mechanism that causes the platform assembly to tilt upward immediately prior to the lifting of the platform assembly, and to tilt downward immediately after the lowering of the platform assembly. The tilting of the platform assembly is accomplished by using the same actuating power system used to lower and raise the platform and does not require a separate actuator or a separate control switch. In a preferred embodiment of the invention, the tilting upward immediately prior to the raising of the platform and the tilting downward is sequenced immediately after the lowering of the platform without requiring any intervening action on the part of the lift user.

[0013] Other objects, features and advantages of the present invention will become apparent to those skilled in the art from the following detailed description. It is to be understood, however, that the detailed description and specific examples, while indicating preferred embodiments of the present invention, are given by way of illustration and not limitation. Many changes and modifications within the scope of the present invention may be made without departing from the spirit thereof, and the invention includes all such modifications.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The invention may be more readily understood by referring to the accompanying drawings in which:

[0015]FIG. 1 depicts a perspective view of a preferred embodiment of the wheelchair lift of the present invention;

[0016]FIG. 2 depicts a top plan view of a preferred embodiment of the wheelchair lift of the present invention;

[0017]FIG. 3 depicts an elevational side view of a preferred embodiment of the wheelchair lift of the present invention;

[0018]FIG. 4 depicts an elevational front view of a preferred embodiment of the wheelchair lift of the present invention;

[0019]FIG. 5 depicts a partial cross-sectional side view of a preferred embodiment of the wheelchair lift of the present invention showing the platform assembly tilted upward;

[0020]FIG. 5A is an enlarged view of the platform tilt mechanism of FIG. 5;

[0021]FIG. 6 depicts a partial cross-section side view of a preferred embodiment of the wheelchair lift of the present invention showing the platform assembly tilted downward;

[0022]FIG. 6A is an enlarged view of the platform tilt mechanism of FIG. 6;

[0023]FIG. 7 is a top plan view of a preferred embodiment of the wheelchair lift of the present invention in an entry level configuration;

[0024]FIG. 8 is a perspective view of a preferred embodiment of the wheel chair lift of the present invention showing the first fold of the two-step folding process of the platform assembly;

[0025]FIG. 9 is a perspective view of a preferred embodiment of the present invention showing the wheelchair lift upon completion of the first fold;

[0026] FIGS. 10A-10C depict the folding process of the second fold in the two-step folding process of the present invention;

[0027]FIG. 11 is a perspective view of a preferred embodiment of the present invention showing the wheelchair lift upon completion of the second fold;

[0028]FIG. 12 is an elevation front view of the folded wheelchair lift shown in FIG. 11;

[0029]FIG. 13 is a top plan view of a preferred embodiment of the floating pivot structural hinge of the present invention, shown in a fully expanded position;

[0030]FIG. 14 is an exploded view of the floating pivot structural hinge of FIG. 13;

[0031]FIG. 15 is a top plan view of the floating pivot structural hinge of FIG. 13, shown in a contracted position;

[0032]FIG. 16 is a cross-section view of the floating pivot structural hinge of FIG. 15 taken along line 16-16;

[0033]FIG. 17 is a partial cut-out perspective view of a preferred embodiment of the floating pivot structural hinge, showing the link members connected to the block hinges; and

[0034]FIG. 18 is an elevational side view of a preferred embodiment of a floating pivot structural hinge of the present invention.

[0035] Like numerals refer to like parts throughout the several views of the drawings.

DETAILED DESCRIPTION OF THE INVENTION

[0036] A preferred embodiment of the single arm wheelchair lift 10 of the present invention is shown in FIGS. 1 through 4. The lift 10 is preferably installed inside a vehicle (not shown) near an opening, such as a side door of the vehicle, to facilitate the ingress and egress of a wheelchair and its occupant. The lift 10 can also be installed near the rear door or any other door of the vehicle. The lift 10 is firmly secured on the doorway of the vehicle by a mounting assembly 12. In a preferred embodiment of the invention, the mounting assembly 12 includes support brackets 14 that extend through the vehicle floor to connect the lift to the underside of the vehicle.

[0037] The mounting assembly 12 is preferably housed in a control tower 16. The control tower 16 also houses the power actuating mechanism 20 for actuating the lift from a folded, stowed configuration (shown in FIG. 11) to an entry level configuration (flush with the vehicle floor, shown in FIG. 3), to a ground level configuration (shown in FIG. 1). For ease of operation, the power actuating mechanism 20 can be powered by electrical, hydraulic or pneumatic means, or other source of energy known to those skilled in the art. For exemplary purposes, a hydraulic actuating system is described herein. In a preferred embodiment of the invention, the hydraulic actuating system includes a hydraulic pump, a hydraulic power unit, and a piston and cylinder assembly 22 operatively connected to the hydraulic pump and the hydraulic power unit.

[0038] The piston and cylinder assembly 22 is preferably installed in a parallelogram actuating linkage structure 30 fixed to the control tower 16. It is envisioned that the parallelogram actuating linkage structure 30 can be replaced with other linkage structures known in the art without departing from the scope and spirit of the present invention. The linkage structure 30 preferably includes a top actuating arm 32 and a bottom actuating arm 34 which are located substantially parallel to each other. The first ends 36, 38 of the top and bottom actuating arms 32, 34 are pivotally connected to the control tower 16. The second ends 42, 44 of the top and bottom actuating arms 32, 34 are pivotally connected to a linking arm 40. In a preferred embodiment of the invention, the linking arm 40 is vertically aligned.

[0039] When the piston and cylinder assembly 22 is extended, the linkage structure 30 causes the linking arm 40 to move upwardly. It is the upward motion of the linking arm 40 that move the lift 10 in an upward direction. When the piston and cylinder assembly 22 retracts, the linkage structure causes the linking arm 40 to move downwardly. It is the downward motion of the linking arm that causes the lift to move toward the ground.

[0040] In a preferred embodiment of the invention, as best shown in FIGS. 1 and 2, the platform assembly 50 of the lift includes first and second rear platforms 52, 54 and first and second front platforms 56, 58. The first and second rear platforms 52, 54 are pivotally attached to each other along line A and the first and second front platforms 56, 58 are also pivotally attached to each other along line B. Furthermore, the rear platforms 52, 54 are pivotally connected to the front platforms 56, 58 along line C. Lines A and B are preferably co-linear when the platform assembly is in a fully extended configuration. Line C is preferably perpendicular to lines A and B. In a fully extended configuration, the front and rear platforms 52, 54, 56, 58 collectively form the surface on which the wheelchair is placed during transport between the entry level and the ground level.

[0041] In the embodiment shown in FIGS. 1 and 2, rear bridge plates 60 are connected to the platform assembly 50. During transport between the entry level and ground level configurations, the bridge plates 60 are positioned in a vertical position with respect to the platform assembly 50 to create a rear barrier for preventing a wheelchair from rolling off the platform assembly. When the lift is at the entry level configuration, as best shown in FIG. 3, the bridge plates 60 move into a horizontal position such that the bridge plates 60 are co-planar with the platform assembly 50 and the vehicle floor. The bridge plates 60 provide a bridge from the platform assembly to the vehicle to ensure safe ingress and egress to the vehicle.

[0042] In addition to the bridge plates 60, the lift 10 of the present invention preferably includes a pair of side barriers 62, 64 and front barriers 66. As shown in FIG. 1, during transport between the entry level and ground level configurations, the side and front barriers 62, 64, 66 are positioned substantially normal to the platform assembly 50, to prevent a wheelchair from rolling off the platform assembly. When the lift is at the ground level configuration, as best shown in FIG. 6, the side and front barriers 62, 64, 66 move downward into a horizontal position such that the barriers provide a smooth transition path for the wheelchair to disembark from the platform assembly onto the ground or to embark the platform assembly from the ground. The side and front barriers 62, 64, 66 are dimensioned such that when the side barriers are down, the platform assembly 50 is accessible by a wheelchair from three different sides. A wheelchair can enter or exit the platform assembly from the left side, the right side or the front of the platform assembly. In some instances, when the lift 10 is at ground level, there may be an obstacle preventing access to the platform assembly from the front. In these situations, it is convenient to provide access to the platform assembly from the sides, in addition to the access from the front. Also, the linking arm 40, as will be described in further detail below, is positioned such that it does not interfere with the movement of the side barrier 62 or a wheelchair's access to the platform assembly from that side.

[0043] In a preferred embodiment of the present invention, the lift 10 includes an automatic platform tilt mechanism 70 to accommodate the roll of the vehicle suspension. The weight of the wheelchair lift installed on one side of the vehicle, together with the weight of the wheelchair and its occupant when loaded thereon, can cause the suspension of the vehicle to roll to one side. When the suspension rolls, the platform assembly tilts downward, away from the vehicle. Because the platform is no longer horizontal, a rider may feel that he or she is not in a safe position. Accordingly, the lift 10 of the present invention, preferably includes an automatic platform tilt mechanism to automatically adjust for the roll of the vehicle suspension.

[0044] The operation of the platform tilt mechanism 70 is best described in reference to FIGS. 5, 5A, 6 and 6A. FIGS. 6 and 6A depict the platform tilt mechanism 70 when the wheelchair lift is at ground level in a tilted down position to facilitate the exit or entry of a wheelchair. In this position, the piston and cylinder assembly 22 is in a fully retracted configuration. The piston and cylinder assembly is preferably pivotally connected to a main platform actuator 72. The main platform actuator 72 is pivotally connected to a first end 76 of a link platform actuator 74. The second end 78 of the link platform actuator 74 is pivotally connected to a lift mechanism cam 80.

[0045] During the tilting process, the lift mechanism cam 80 interacts with a cam follower 82. The cam follower 82 is preferably attached to a first end 86 of the platform actuator bar 84. The second end 88 of the platform actuator bar 84 is connected to the platform assembly 50. In a preferred embodiment of the invention, the second end 88 of the platform actuator bar 84 is connected to the first front platform 56 at connection point 90. Connection point 90 is preferably adjacent to line C (best shown in FIG. 2). The linking arm 40 is also pivotally connected to the first front platform 56 at connection point 92. Connection point 92 is preferably spaced apart from connection point 90 and is farther from line C than connection point 90.

[0046] As best shown in FIGS. 5 and 5A, as the piston and cylinder assembly 22 extends in the direction E, the first end 76 of the link platform actuator 74 moves in the same direction as the piston and cylinder assembly. As the first end 76 moves in direction E, the second end 78 moves in the opposite direction, causing the link mechanism cam 80 to rotate. The link mechanism cam 80 exerts force on the cam follower 82, which causes the platform actuator bar 84 to move in a downward direction. When forced downward, the platform actuator bar 84 exerts force on the first front platform 56 at connection point 90, causing the first and second front platforms 56, 58 to rotate about connection point 92. As the front platforms 56, 58 rotate about connection point 92, the front end 94 of the platform assembly 50 tilts upward.

[0047] The platform tilt mechanism 70 is configured to tilt the platform assembly 50 to the extent that it accommodates for the roll of the vehicle suspension. The platform tilt mechanism 70 of the present invention does not require a separate actuator system or control switch. It utilizes the same power actuating mechanism 20 that operates the lift from a stowed configuration to an entry level configuration, and to a ground level configuration. The tilt mechanism 70 is simply an initial operation that is automatically performed upon lifting and landing.

[0048] When the platform assembly 50 is lifted off the ground, the tilt mechanism 70 tilts the platform assembly as described and the main platform actuator 72 contacts the inner surface 46 of the linking arm 40. Thereafter, the main platform actuator 72 can not move any further, and as the piston and cylinder assembly 22 continues to expand, the tilting stops and the lifting of the linking arm 40 commences. Thus, the wheelchair lift 10 of the present invention automatically sequences the lifting operation to commence upon completion of the tilting operation.

[0049] During the landing (or lowering) process, the sequencing occurs in reverse order, i.e., the landing operation commences first and when the platform assembly is at ground level, the tilting operation commences to ensure that the front end 94 of the platform assembly reaches the ground. During the lowering process, when the lift 10 has arrived at ground level, as best shown in FIGS. 6 and 6A, the piston and cylinder assembly 22 continues to retract, causing the first end 76 of the link platform actuator 74 to move in the direction R. The link platform actuator 74 moves away from the inner surface 46 of the linking arm 40. As the first end 76 moves in direction R, the second end 78 moves in the opposite direction E, causing the link mechanism cam 80 to rotate. The link mechanism cam 80 rotates on the cam follower 82, which causes the platform actuator bar 84 to move in an upward direction. When the force of the cam 80 on the cam follower 82 is removed, the platform actuator bar 84 lifts the first front platform 56 at connection point 90, causing the first and second front platforms 56, 58 to rotate about connection point 92. As the front platforms 56, 58 rotate about connection point 92, the front end 94 of the platform assembly 50 tilts downward. The platform assembly 50 comes to rest in the same plane as the ground on which it has landed, allowing the front and side barriers to operate in a variety of ground tilts. Accordingly, the tilt mechanism 70 ensures that there is no gap remaining between the front end 94 of the platform assembly 50 and the ground.

[0050] When the wheelchair lift is not in use, it is folded into a storage configuration and stored inside the vehicle. Because the platform assembly must fit vertically through the vehicle doorway, the length of the platform assembly has traditionally been limited by the height of the vehicle doorway. The height of a typical van doorway is about 47 inches. If the height of the van doorway is expanded (modified), it is possible to fit a 52 inch platform assembly through the doorway. In a preferred embodiment of the present invention, due the manner in which the wheelchair lift folds, a longer platform assembly can fit through the vehicle doorway without requiring an expansion or other modification to the doorway.

[0051] The folding process of a preferred embodiment of the wheelchair lift is now described. In reference to FIGS. 5 and 5A, as the wheelchair lift rises from the ground level configuration to the entry level configuration, the piston and cylinder assembly 22 is expanding, causing the linkage structure 30 to lift up the linking arm 40. During the movement of the linkage structure 30, the fold mechanism cam 100 approaches the cam follower 82 (also shown in FIG. 3). As the wheelchair lift moves from the entry level configuration to the storage configuration, the fold mechanism cam 100 contacts the cam follower 82. The fold mechanism cam 100 exerts force on the cam follower 82, which causes the platform actuator bar 84 to move in a downward direction. When forced downward, the platform actuator bar 84 exerts force on the first front platform 56 at connection point 90, causing the first and second front platforms 56, 58 to rotate about connection point 92.

[0052] In reference to FIGS. 5 and 7, the rear platforms 52, 54 are pivotally connected to the front platforms 56, 58 along line C. Because connection point 90 is positioned adjacent line C, when the platform actuator bar 84 exerts force at connection point 90, the rear platforms 52, 54 begin to fold toward the front platforms 56, 58 as best shown in FIG. 8. The force exerted at connection point 90 also causes the front platforms 56, 58 to rotate about connection point 92. As the front platforms 56, 58 rotate about connection point 92, the front and rear platforms 52, 54 continue to fold toward each other until the rear platforms 52, 54 are in a substantially parallel facing relationship with the front platforms 56, 58, as shown in FIG. 9.

[0053] The folding operation of the present invention folds the platform assembly into quadrants. The first fold is a crosswise fold, as described above. The second fold is a lengthwise fold, shown best in FIGS. 10A-10C. When the two-fold process is completed, the platform assembly is folded into quadrants.

[0054] The second fold of the two-fold process is now described. As best shown in FIG. 9, the wheelchair lift 10 preferably includes a fold actuator 110 to facilitate the second fold of the two-fold process. In a preferred embodiment of the invention, the fold actuator 110 is preferably an electrical actuator, and more preferably, an actuator as described in U.S. Provisional Patent Application No. 60/386,338 filed Jun. 6, 2002 and Ser. No. ______ for Clutch-Driven Limited Force Actuator filed concurrently herewith, the contents of which are incorporated herein by reference. However, it is within the scope of the present invention to utilize a piston and cylinder assembly or other known actuators as fold actuator 110. The fold actuator 110 is operatively connected with the power actuating mechanism 20 of the present invention. After the first fold of the two-fold process is completed, the fold actuator 110 is activated to exert force on the second side 104 of the platform assembly 50. By exerting force on the second side 104, the second side 104 begins pivot with respect to the first side 102 and to rotate about axis Z.

[0055] The second fold process is best shown in FIGS. 10A-10C, which show a top plan view of the lift during the folding process. FIG. 10A depicts a preferred embodiment of the invention after the first fold is completed but before the second fold has commenced. FIG. 10B depicts the lift as the fold actuator 110 exerts force on the second side 104 of the platform assembly 50, causing the second side 104 to pivot with respect to the first side 102. To assist in the lengthwise folding of the platform assembly, a torsion spring (not shown), connects the first and second sides 102, 104 of the platform assembly. The torsion spring biases the platform assembly in the folding direction and facilitates the folding once it is initiated by the fold actuator 110. FIG. 10C depicts the lift at the completion of the two step folding process, when the second (lengthwise) fold has been completed.

[0056] In a preferred embodiment of the invention, as best shown in FIGS. 7 and 10A-C, the second side 104 of the platform assembly 50 is wider than the first side 102. The purpose of offsetting the pivot line on the platform assembly, and thus making the second side 104 wider than the first side 102 is to enhance the clearance of the vehicle doorway when the lift is in a stowed configuration. When the lengthwise fold is completed, as shown in FIG. 10C, the second side 104 of the platform assembly 50 is completely cleared out of the vehicle doorway. As shown in FIGS. 10C and 11, the second side 104 of the platform assembly 50 preferably extends behind the first side 102 at an angle, and more preferably, at about a 45 degree angle. In a stowed configuration, as best shown in FIG. 12, the width of the wheelchair lift is also minimized as the second side 104 of the wheelchair lift is cleared out of the doorway. Accordingly, most of the vehicle doorway is left clear.

[0057] To allow the various platforms 52, 54, 56, 58 to fold with respect to each other, the platforms are interconnected by pivotable connection devices. It is within the scope of the invention to use any type of connection device that allows the platforms to pivot with respect to each other. In a preferred embodiment of the invention, as shown in FIG. 7, hinges are used to pivotally connect the platforms to each other. A first hinge 120 connects the rear platforms 52, 54 to the front platforms 56, 58 along line C; a second hinge 122 connects the first rear platform 52 to the second rear platform 54 along line A; and a third hinge 200 connects the first front platform 56 to the second front platform 58.

[0058] To enable the platform assembly 50 to fold crosswise along line C during the first fold of the two-fold process, the hinges 120 must have a common pivot axis. Accordingly, the hinges 120 are all preferably positioned along line C such that the pivot axis of each hinge is along line C. When the pivot axes of the hinges 120 are aligned, the rear platforms 52, 54 fold with respect to front platforms 56, 58 about line C.

[0059] After the first fold of the two-fold process is completed, the rear platforms 52, 54 are folded and in a facing relationship with the front platform 56, 58. Thus, for the second fold of the two-fold process (the lengthwise fold), the second rear platform 54 and second front platform 58 must fold together. The second rear platform 54 pivots with respect to the first rear platform 52 about line A and the second front platform 58 pivots with respect to the first front platform 56 about line B. To allow the second rear platform 54 and the second front platform 58 to fold together, pivot line A must be aligned with pivot line B. If the pivot lines are not aligned, neither platform will be able to fold in the lengthwise direction. Accordingly, it is within the scope of the invention to use any connection device to connect the rear platforms 52, 54 to each other and the front platforms 56, 58 to each other, as long as the connection devices pivot about a common axis during the second fold of the two-step folding process.

[0060] In a preferred embodiment of the present invention, as shown in FIG. 10B, when the platform assembly is folded in a lengthwise direction, the second hinge 122 is positioned inside the third hinge 200. As discussed, to enable the second (lengthwise) fold of the platform assembly, the pivot axis of the second hinge 122 must be aligned with the pivot axis of the third hinge 200. However, the second hinge 122 is not vertically aligned with the third hinge 200. Rather, as shown in FIG. 10B, the second hinge 122 lies inside the third hinge 200. Accordingly, the types of hinges used must be selected to ensure that the pivot axis of the second hinge 122 aligns with the pivot axis of the third hinge 200 when the platform assembly folds in the lengthwise direction.

[0061] In a preferred embodiment of the invention, the second hinge 122 is a piano hinge connected along line A and having a pivot axis along line A. The third hinge 200 is connected along line B, however, does not have a pivot axis along line B, because as shown in FIG. 10B, after the first (crosswise) fold of the two-fold process is completed, lines A and B are not co-linear. Therefore, to allow the platform assembly to fold again, this time in the lengthwise direction, the third hinge 200 must be a type of hinge that is connected along line B, however, when pivoted, pivots along an axis that is colinear with line A.

[0062] A preferred embodiment of the third hinge 200 is described in references to FIGS. 13 through 18. It is envisioned that any known connection device can be used that would allow the platforms to fold in the manner described above. As shown in FIG. 13, the third hinge 200, although physically positioned along line B, has a pivot axis Z lying outside the hinge. This allows the pivot axis Z of the third hinge to be aligned with the pivot axis (line A) of the second hinge 122 to facilitate the lengthwise folding of the platform assembly.

[0063] As best shown in FIGS. 14 through 18, the third hinge 200 includes a first block hinge 202 and a second block hinge 204. The first and second block hinges 202, 204 are interconnected by a plurality of link members 206. For exemplary purposes, four link members 206 are shown. Each link member 206 has a first end 208 pivotally connected to one of the block hinges 202, 204 and a second end 210 slidably connected to the other block hinges 202, 204. Furthermore the link members 206 are each pivotally connected to each other along line B. In a preferred embodiment of the invention, each link member 206 has a first aperture 212 at its first end 208, a second aperture 214 at its second end 210, and a third aperture 216 at a common point 218. To pivotally link the link members 206 with the block hinges 202, 204, the first apertures 212 at the first end 208 of the link members 206, are aligned with corresponding apertures 220 on the block hinges 202, 204. Upon alignment of the apertures 212 and 220, a pin 222 is inserted through the aligned apertures 212, 220 to pivotally connect the links 206 with the block hinges 202, 204. To slidably engage the second ends 210 of the link members 206 with the block hinges 202, 204, the second apertures 214 are aligned with a slot 224 in the block hinges 202, 204, and a pin 222 is inserted through the aligned apertures 214 and slot 224. The link members 206 are preferably arranged in an alternate configuration. In other words, the first link member 206 a is preferably slidably connected to the first block hinge 202 and pivotally connected to the second block hinge 204, while the second link member 206 b is pivotally connected to the first block hinge 202 and slidably connected to the second block hinge 202, and so on. Spring clips 226, spacers 228 and bushings 230 may be used, as known in the art, to ensure smooth installation and movement of the link members 206.

[0064]FIGS. 15 and 16 depict the third hinge 200 in a contracted configuration. In this configuration, the second ends 210 of the link members 206 are positioned at the outer ends 232 of the slots 224. As the third hinge expands (shown in FIG. 13) the second ends 210 of the link members 206 move toward the inner ends 234 of the slots. In the fully expanded position, as shown in the FIG. 13, the second ends 210 of the link members 205 are positioned at the inner ends 234 of the slots.

[0065] The embodiments described above are exemplary embodiments of a single arm wheelchair lift. Those skilled in the art may now make numerous uses of, and departures from, the above-described embodiments without departing from the inventive concepts disclosed herein. Accordingly, the present invention is to be defined solely by the scope of the following claims. 

What is claimed is:
 1. A wheelchair lift for use in conjunction with a vehicle, the wheelchair lift comprising: a platform assembly having a first inner platform, a second inner platform, a first outer platform, and a second outer platform; wherein the first inner platform is pivotally connected to the second inner platform; wherein the first outer platform is pivotally connected to the second outer platform; wherein the first and second inner platforms are pivotally connected to the first and second outer platforms; and a storage configuration wherein the first and second inner platforms fold crosswise with respect to the first and second outer platforms, and the second inner platform and second outer platform fold lengthwise with respect to the first inner platform and first outer platform.
 2. A wheelchair lift having a platform assembly foldable in a first crosswise fold and in a second lengthwise fold.
 3. The wheelchair lift of claim 2 wherein the first crosswise fold and second lengthwise fold are not parallel.
 4. The wheelchair lift of claim 2 wherein the first crosswise fold and second lengthwise fold are perpendicular.
 5. A method of folding the platform assembly of a wheelchair lift, the method comprising the steps of: folding the platform assembly crosswise; and folding the platform assembly lengthwise.
 6. The method of claim 5 wherein the step of folding the platform assembly lengthwise follows the step of folding the platform assembly crosswise.
 7. A wheelchair lift for use in conjunction with a vehicle, the wheelchair lift comprising: a platform assembly having a first inner platform, a second inner platform, a first outer platform, and a second outer platform; a first fold actuating assembly configured to pivot the first and second inner platforms with respect to the first and second outer platforms; and a second fold actuating assembly configured to pivot the second inner and outer platforms with respect to the first inner and outer platforms.
 8. The wheelchair lift of claim 7 wherein the first fold actuating assembly comprises: a linking arm pivotally connected to the platform assembly at a first connection point; a platform actuator bar connected to the platform assembly at a second connection point, the platform actuator bar configured to exert force on the platform assembly at a second connection point in a manner that causes the platform assembly to rotate about the first connection point.
 9. The wheelchair lift of claim 8 wherein the fold actuating assembly further comprises a fold mechanism cam engageable with a cam follower on the platform actuator bar, wherein the fold mechanism cam contacts the cam follower and exerts force on the platform actuator bar.
 10. The wheelchair lift of claim 7 wherein the second fold actuating assembly comprises a piston and cylinder assembly.
 11. The wheelchair lift of claim 10 further comprising a power actuating system wherein the piston and cylinder assembly is in operative communication with the power actuating system.
 12. A wheelchair lift for use in conjunction with a vehicle, the wheelchair lift comprising: a platform assembly having a first inner platform, a second inner platform, a first outer platform, and a second outer platform; a first fold actuating assembly configured to pivot the first and second inner platforms with respect to the first and second outer platforms the first fold actuating assembly comprising a linking arm pivotally connected to the platform assembly at a first connection point, a platform actuator bar connected to the platform assembly at a second connection point, the platform actuator bar configured to exert force on the platform assembly at a second connection point in a manner that causes the platform assembly to rotate about the first connection point; and a second fold actuating assembly configured to pivot the second inner and outer platforms with respect to the first inner and outer platforms, wherein the second fold actuating assembly comprises a piston and cylinder assembly.
 13. A wheelchair lift for use in conjunction with a vehicle, the wheelchair lift comprising: a platform assembly having a first inner platform, a second inner platform, a first outer platform, and a second outer platform; a first hinge pivotally connecting the first inner platform to the second inner platform, the first hinge having a first pivot axis; a second hinge pivotally connecting the first and second inner platforms to the first and second outer platforms, the second hinge having a second pivot axis; a third hinge pivotally connecting the first outer platform to the second outer platform having a third pivot axis; and a storage configuration wherein the first and second inner platforms fold crosswise with respect to the first and second outer platforms about the first pivot axis, and the second inner platform folds lengthwise with respect to the first inner platform about the second pivot axis, and the second outer platform folds lengthwise with respect to the first outer platform about a third pivot axis, wherein the second and third pivot axes are colinear.
 14. The wheelchair lift of claim 13 wherein the third pivot axis is spaced apart from the third hinge.
 15. The wheelchair lift of claim 13 wherein the third hinge comprises: a first block hinge; a second block hinge; and a plurality of link members connecting the first block hinge to the second block hinge, each link member having a first end, a second end and a common portion, the first end of each link member pivotally connected to one of the first and second block hinges, the second end of each link member slidably engaged to the other of said first and second block hinges, and the common portions of the plurality of link members pivotally connected to each other.
 16. The wheelchair lift of claim 15 wherein the third hinge comprises a first link member pivotally connected to the first block hinge and slidably engaged with the second block hinge, and a second link member adjacent the first link member, the second link member pivotally connected to the second block hinge and slidable engaged with the first block hinge.
 17. The wheelchair lift of claim 16 wherein the first and second block hinges each comprises a slot therein, the slot having an outer side and an inner side, the third hinge further comprising a contracted configuration wherein the first block hinge is adjacent the second block hinge and wherein the second end of the first link member is positioned at the outer side of the slot in the second hinge block and the second end of the second link member is positioned at the outer side of slot in the first hinge block.
 18. The wheelchair lift of claim 13 wherein the second hinge is a piano hinge.
 19. A floating pivot hinge having a pivot axis spaced apart therefrom, the floating pivot hinge comprising: a first block hinge; a second block hinge; and a plurality of link members connecting the first block hinge to the second block hinge, each link member having a first end, a second end and a common portion, the first end of each link member pivotally connected to one of the first and second block hinges, the second end of each link member slidably engaged to the other of said first and second block hinges, and the common portions of the plurality of link members pivotally connected to each other.
 20. A floating pivot hinge having a pivot axis spaced apart therefrom, the floating pivot hinge comprising: a first block hinge; a second block hinge; a first link member pivotally connected to the first block hinge and slidably engaged with the second block hinge; and a second link member adjacent the first link member, the second link member pivotally connected to the second block hinge and slidably engaged with the first block hinge.
 21. The floating pivot hinge of claim 20 wherein each of the first and second block hinges comprise a slot for slidably engaging the link members.
 22. The floating pivot hinge of claim 20 wherein each of the first and second link members comprise a common portion and are pivotally connected at the common portion.
 23. A floating pivot hinge having a pivot axis spaced apart therefrom, the floating pivot hinge comprising: a first block hinge and a second block hinge, each of the first and second block hinges having a slot therein; a first link member pivotally connected to the first block hinge and slidably engaged with the slot of the second block hinge; a second link member adjacent the first link member, the second link member pivotally connected to the second block hinge and slidably engaged with the slot of the first block hinge; and wherein the first and second link members each have a common portion and are pivotally connected to each other at the common portion.
 24. A wheelchair lift comprising a platform assembly, the platform assembly having a front end, a first side and a second side opposite the first side, wherein the platform assembly is configured to allow a wheelchair access thereon from the front end, first side and the second side.
 25. A wheelchair lift, comprising: a power actuating system; a platform assembly having a first end; an automatic platform tilt mechanism operatively connected to the power actuating system, wherein the automatic platform tilt mechanism is configured to tilt the first end of the platform assembly.
 26. A method of operating a wheelchair lift, comprising the steps of: providing a power actuating system, a platform assembly having a first end, and an automatic platform tilt mechanism; tilting the first end of the platform assembly upward; and lifting the platform assembly; wherein the power actuating source provides power for both tilting and lifting the platform assembly, wherein lifting the platform assembly is sequenced immediately after the tilting and requires no intervening action.
 27. A method of operating a wheelchair lift, comprising the steps of: providing a power actuating system, a platform assembly having a first end, and an automatic platform tilt mechanism; tilting the first end of the platform assembly downward; and lowering the platform assembly; wherein the power actuating source provides power for both tilting and lowering the platform assembly, wherein the tilting downward is sequenced immediately after lowering the platform assembly and requires no intervening action.
 28. A method of operating a wheelchair lift, comprising the steps of: providing a power actuating system, a platform assembly having a first end, and an automatic platform tilt mechanism; lowering the platform assembly; raising the platform assembly; wherein the platform tilt mechanism tilts the platform downward immediately after lowering the platform assembly to the ground level, without any intervening action by the user; wherein the platform tilt mechanism tilts the platform assembly upward immediately before raising the platform assembly, without any intervening action by the user; wherein the power actuating source provides power for the tilting, raising and lowering of the platform assembly.
 29. The method of claim 28 wherein the platform tilt mechanism comprises: a linking arm pivotally connected to the platform assembly at a first connection point; and a platform actuator bar connected to the platform assembly at a second connection point, the platform actuator bar configured to exert force on the platform assembly at a second connection point in a manner that causes the platform assembly to rotate about the first connection point.
 30. The method of claim 29 wherein the platform tilt mechanism further comprises a lift mechanism cam engageable with a cam follower on the platform actuator bar, wherein the fold mechanism cam contacts the cam follower and exerts force on the platform actuator bar.
 31. A platform tilt mechanism for tilting the platform assembly of a wheelchair lift, the tilt mechanism comprising: a linking arm pivotally connected to the platform assembly at a first connection point; and a platform actuator bar connected to the platform assembly at a second connection point, the platform actuator bar configured to exert force on the platform assembly at a second connection point in a manner that causes the platform assembly to rotate about the first connection point.
 32. The tilt mechanism of claim 31 wherein the platform tilt mechanism further comprises a lift mechanism cam engageable with a cam follower on the platform actuator bar, wherein the fold mechanism cam contacts the cam follower and exerts force on the platform actuator bar. 